Sprocket-wheel.



No. 817,632. PATENTED APR. 10, 1906.

J. M. DODGE. SPROOKBT WHEEL.

APPLIUATION FILED MAY23, 1898.

2 SHEETS-SHEET 1.

FIG. 1.

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...1llii No. 817,632. PATENTED APR.10,19 06. J. M. DODGE.

SPROOKET WHEEL.

APPLICATION TILED MAY23.1898.

2 SHBETS-SHEET 2.

} MI ym UNITED STATES PATENT OFFICE.

SPFIOCKET-WHEEL.

Specification of Letters Patent.

Patented April 10, 1906.

Application filed May 23, 1898. Serial No- 681,467-

To ctZZ whom it may concern:

Be it known that I, JAMES M. DODGE, a citizen of the United States,residing in Philadelphia, Pennsylvania, have invented certainImprovements in Sprocket-Wheels for Drive- Chains, of which thefollowing is a specification.

The object of my invention is to so construct a sprocket-wheel fordrive-chains that chains links of one size and Fig. 4 is a view similarto Fig. 3, showing links of another size.

Heretofore in the manufacture of drivechains and sprocket-wheelstherefor great care had to be exercised in fitting a chain to asprocket-wheel, and each wheel had to be tested and fitted accurately toeach link of a chain before it was placed in position for actual use.Consequently the expense of manufacture was increased and it wasimpossible to substitute one wheel for another without accuratelyfitting it to the chain.

By my invention I am enabled to place a chain on a sprocket-wheelwithout special fitting, which chain will run accurately on thebearing-surface of the teeth and without undue wear or friction.

A is the wheel, which may be of any diameter and of the shape shown, andthis wheel has in the present instance a series of V- shaped teeth awith the same bevel on one side as on the other, so that the wheel canbe reversed, as the chain when running on the wheel only bears upon onesurface of the tooth.

As shown in Fig. 3, the chain B rests against the inclined surface a ofeach tooth, the chain being the ordinary form of detachable link chainhaving a socket at one end and a bar at the opposite end adapted to thesocket of the adjoining link. It will be seen that the periphery of thesocket alone bears upon the surface of the tooth and that the cross-barswivels in the socket, so that when the link seats itself on the wheelthere is no motion, and as the chain leaves the wheel the angle is suchthat as soon as the link swings on its pivot the socket will at onceleave the bearing-face of the tooth. Consequently there is very littleabrasion of the teeth. In the manufacture of such chain-links the lengthof the links differs materially owing to the differences in the materialor process of manufacture, and it is this feature that makes it almostimpossible to make a sprocket-wheel of the usual character having teethwhich will accurately fit the links of the chain. By making thebearing-face a of the teeth of the wheel at such an angle that the chainWill find its own pitch-line and the teeth will resits thrust toward theaXis of the wheel, as well as the pulling strain, I entirely overcomethe difiiculty above mentioned in fitting the chain to thesprocket-wheel, as the several links of the chain will accommodatethemselves to the wheel and seat themselves properly thereon, and as theteeth and chain wear they Will accommodate'themselves to the difference,so that the relation between the wheel and the chain is always the same.

In Fig. 3 I have shown adapted to the Wheel a chain having long links,and it will be noticed that the pitch-line of the chain is near theperiphery of the Wheel, whereas in Fig. 4 I have shown a chain havingshort links adapted to the teeth of the wheel and the pitch-line isnearer the center of the Wheel but it will be noticed that in eithercase the chain rests solely upon the inclined bearingface of the tooth.The gullet between the teeth is so deep that a chain that would freeitself in passing off of the wheel could not possibly seat itself in thebase of the gullet.

Sprocket wheels as usually made have a root diameter which is the lineof rest for the links of the chain, whereas in my improvedsprocket-wheel the angular surfaces of the teeth provide the solesupport for the links of the chain, and the ordinary chain is used-thatis to say, a chain having open rectangular links with the line ofarticulation of the links within the outside diameter of the wheelnoespecial form of chain being necessary.

Having thus described my invention, I claim and desire to secure byLetters Patent- 1. The combination in a sprocket-wheel having a seriesof V-shaped teeth all lying in the same plane, with an open-link chainarranged to pass around said wheel, the teeth of the wheel extendinginto the open links of the chain and the transverse members of theradius of the Wheel, with an open-link chain arranged to pass around theWheel, the teeth of the said Wheel passing through the open links of thechain and the bearing-points being on the pitch-line of the chain,substan tially as described.

In testimony whereof I have signed my name to this specification in thepresence of tWo subscribing Witnesses.

JAMES M. DODGE.

Witnesses:

HENRY HoWsoN, Jos. H. KLEIN.

